Förbelastning

Förbelastning, often translated as preloading or prestressing, is a technique used in engineering to intentionally introduce internal stresses into a structure or component before it is subjected to its intended service loads. This is typically achieved by applying a controlled external force during the manufacturing or construction process that induces compression or tension in specific areas.

The primary purpose of förbelastning is to improve the load-carrying capacity and structural integrity of a member. By counteracting the tensile stresses that will develop under service loads with pre-existing compressive stresses, the material can be utilized more efficiently and its resistance to cracking or failure is enhanced. This is particularly common in concrete structures, such as bridges and buildings, where concrete has a low tensile strength. Prestressing concrete members allows for longer spans and thinner sections while maintaining structural soundness.

Förbelastning can be applied through various methods. In prestressed concrete, steel tendons are tensioned and then anchored, either before or after the concrete hardens. In other applications, such as bolted connections, controlled tightening of bolts can create a significant clamping force, preloading the joint. The magnitude and distribution of these initial stresses are carefully calculated to optimize the performance of the structure under its expected operational conditions. The application of förbelastning requires precise control to ensure the desired internal stress state is achieved and maintained.